Kathryn is a 14-year-old girl on the home front in small-town Ontario fighting a war of her own against a gang of local bullies who threaten Avery and April, a brother and sister from the wrong side of the tracks. Inspired and awed by April's move to join a boys-only soap box derby, Kathryn builds her own car and submits her official entry form. But when the competition assumes she is April's ally, Kathryn is forced to endure the sting of gossip and threat of sabotage. The cost of being different tests her loyalty to April and soon reveals her family's own prejudices. But with the help of a local sponsor and her best friend Carrie, Kathryn commits to a battle of wills that promises a neck-and-neck finish. Can Kathryn beat the boys at their own game or will her plan go off the tracks?